I'm not sure if I agree on that. when we think about viral we think about one existing user is inviting another one. This is not the case just because you are o

I'm not sure if I agree on that. when we think about viral we think about one existing user is inviting another one. This is not the case just because you are on the store if your app does not add more value to the user then they invite a friend. Facebook is one of these examples. Your Facebook is better when your friends are in there. For this reason you invite them. An app that you use to hide some of your pictures is not getting any better just because your friends are using it. Still good reviews and a good placement in the market makes finding and trusting you easier for the user. But if you don't get up in the ranks or search results there is nothing that gets you anywhere. Where as if you have a viral loop in your app, you can still grow even if you don't rank in the store.